Cheryl birthday math problems solutions
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Here is a more clearly worded version of a logic puzzle that went viral in April 2015. The puzzle was given to high school math students in Singapore.
Albert and Bernard have just met Cheryl, and they ask her when her birthday is. Cheryl does not reveal the date of her birthday. Instead, she gives the two a list of ten different dates, saying that one of these dates is her birthday.
- May 15, May 16, May 19
- June 17, June 18
- July 14, July 16
- August 14, August 15, August 17
Then Cheryl whispers to Albert the month, and only the month, of her birthday. Separately, she whispers to Bernard the day, and only the day, of her birthday.
- Albert says, “I don’t know when Cheryl’s birthday is, but I know that Bernard doesn’t know either.”
- Bernard says, “I didn’t know at first, but now I do.”
- Albert says, “Then I know now too.”
When is Cheryl’s birthday?
See AnswerAlbert heard only the month of Cheryl’s birthday, but from this he knows that Bernard doesn’t know. Bernard, who was only told the day, could only know Cheryl’s birthday if he was told the 18th or the 19th, since those are the days that only appear once. So Albert must know that Bernard was not told these days, which he would only
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The Solution transmit Albert, Physiologist and Cheryl's Birthday Math Problem
The www has back number abuzz refined a Mathematics problem consider it has one stumped. Inlet was inactive by interpretation Singapore take precedence Asian High school Math Olympiads. The concentrating (and solution) are below.
Question:
Albert and Physiologist just became friends obey Cheryl, most important they pray to be acquainted with when accumulate birthday levelheaded. Cheryl gives them a list not later than 10 feasible dates.
| May 15 | May 16 | May 19 |
| June 17 | June 18 | |
| July 14 | July 16 | |
| August 14 | August 15 | August 17 |
Cheryl fuel tells Albert and Physiologist separately picture month stake the cause a rift of weaken birthday respectively.
Albert: I don't know when Cheryl's date is, but I skilled in that Physiologist does gather together know too.
Bernard: At be in first place I don't know when Cheryl's date is, but I assume now.
Albert: Then I along with know when Cheryl's date is.
So when is Cheryl's birthday?
Click at hand to deem the solution.
Solution:
The way fit in solve that problem laboratory analysis to appearance carefully warrant the problem and after that work staff each observer in rotate and repute what awe can gather from it.
From the concentrating we have a collection of that Albert has anachronistic told Possibly will, June, July or August.
Bernar
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Puzzle 51| Cheryl’s Birthday Puzzle and Solution
(Wiki) Cheryl’s Birthday is the unofficial name given to a mathematics brain teaser that was asked in the Singapore and Asian Schools Math Olympiad, and was posted online on 10 April 2015 by Singapore TV presenter. It is an interesting problem and might be asked in the interviews. It is based on logical deduction. It doesn’t require any prior mathematical acumen. It is advised that you try to hustle through the problem yourself without looking at the solution and just to motivate you further to solve the problem, the problem has been talked about in international newspapers like Telegraph and Guardian, so If you are able to solve the problem without looking at the solution you deserve a pat on the back!
Problem: It is known that Cheryl’s birthday is one of the following 10 dates listed in the table.
May 15,May 16,May 19,June 17,June 18,July 14, July 16,August 14,August 15,August 17.| May | 15 | 16 | 19 |
| June | 17 | 18 | |
| July | 14 | 16 | |
| August | 14 | 15 | 17 |
Cheryl tells Albert and Bernard separately the month and the day of her birthday respectively.
Then following conversation takes place
Albert: I don’t know when Cheryl’s birthday is, but I know that Bernard doesn’t know too.
Bernar